Stihl Guide / Workshop reference / 1115

STIHL 056 ignition replacement: Bosch, SEM, Magnum and concrete-saw options

Technical field guide · 045/056 family · Research checked 17 October 2026

A dead ignition does not automatically retire an 056. There are factory-documented replacement paths, specialist aftermarket assemblies, repairable Bosch failures and useful donor machines. The expensive mistake is buying by the words “fits 056” without identifying the ignition and flywheel already fitted.

This guide covers the 056, 056 Super and Magnum/Magnum II, with related 045 components where relevant. It separates factory documentation, seller fitment claims and first-hand repair reports. None of the replacements discussed here was bench-tested for this article.

The short answer

• Already Bosch electronic? A correctly specified Bosch-electronic replacement is the first buying option to investigate. Repairing the original Bosch unit is also worth considering.
• Already later SEM GA? Investigate the original-style 1108 400 0800 replacement. Do not buy a Bosch replacement and expect it to work with the SEM flywheel.
• Early SEM GE? Price a complete, matched conversion before buying another old module. GE and GA are not the same ignition.
• Considering a TS350/TS360 donor? The module connection is real. The flywheel is the trap.
• “Magnum ignition” in a listing? That is a model description, not enough information to establish compatibility or a performance upgrade.

The evidence and qualifications behind these recommendations follow below.

1. Identify the system—not just the badge

Start with photographs of the module/stator, its markings, both sides of the flywheel, and the starter engagement. Preserve any numbers before cleaning them aggressively. Record what is actually installed: a decades-old saw may have been converted more than once.

The STIHL service manual, printed pp. 28–29 explains the Bosch arrangement and explicitly distinguishes electronic and points flywheels. The first-hand ignition-identification discussion supplies the GE identification details; those are field reports, not a substitute for inspecting the parts.

Terminology matters. Sellers use coil, module, magneto, stator and ignition assembly loosely. Ask whether the offer is a bare high-tension coil, a populated plate, or a complete plate-and-flywheel set. A shared label does not establish shared contents.

2. What “Magnum” does—and does not—tell you

STIHL's Magnum II introduction describes a larger-cylinder development of the 056, including changes to the crankcase, cylinder/piston and carburetor. That is not evidence that a loosely advertised “Magnum coil” creates a more powerful ignition or converts a standard 056 into a Magnum. STIHL T.9.85, PDF p. 34.

For ignition purchasing, treat 056 / Super / Magnum as the starting filter, then identify the installed system. The later parts book covers 056, 056 S and 056 M and lists the replacement ignition in the shared starter/ignition section. 056 parts book, illustration H.

Consequently, a Magnum donor may be useful, but only because it carries the required parts—not because the nameplate guarantees a special or universally interchangeable ignition. There is no substantiated spark-energy or horsepower comparison behind the recommendations in this guide.

3. The part numbers worth recording

These are identification references, not a shopping list to order indiscriminately.

Sources: factory changeover summary, PDF p. 39, 056 IPL, and TS360 IPL.

Two additional numbers deserve caution:

• 1115 400 1207: repairers identify this as the early SEM GE flywheel. It is a useful search lead, not a factory-catalog-verified cross-reference in this investigation. Identification discussion.
• 1108 400 0810: appears alongside 0800 in a seller's GA replacement listing. That establishes the seller's claimed coverage, not a complete STIHL supersession history. Chainsawr's GA/NOS listing.

4. The factory SEM conversion—and the mis-stamped flywheel trap

STIHL T.13.85 documents a new system beginning at X 14 038 764. Its module and flywheel must be installed together when replacing the previous Bosch or earlier SEM arrangement. That is a documented assembly conversion, not permission to mix individual generations. Factory bulletin, PDF p. 37.

The unusually important detail is on its third page: some 1115 and 1108 flywheels were marked with each other's numbers. STIHL gives these large-end taper-bore diameters:

These are identification dimensions, not machining instructions or manufacturing tolerances. Require a bore measurement as well as a photograph of the stamp when buying an uncertain flywheel. STIHL T.13.85, PDF p. 39.

The scanned bulletin also contains an apparent introductory part-number error; its summary and the later IPL agree on the pair shown in section 3. Use those corroborated references, not an isolated sentence copied into a sales description.

5. If you have Bosch electronic ignition

A. Buy the Bosch-electronic-specific aftermarket assembly

Sägenspezi lists SKU 13705AR1951 for 045/056 Bosch and Ducati electronic systems. It expressly excludes SEM and the breaker/condenser configuration. Its comparison number is 1110 400 0507; that seller cross-reference should not be mistaken for the 1115… assembly numbers above. Sägenspezi electronic product.

This is the most straightforward replacement candidate when the existing Bosch-electronic flywheel is correct and serviceable. That recommendation is about avoiding extra conversion parts, not a measured reliability ranking.

A 2021 owner reports using a Sägenspezi unit in a Bosch-equipped 056. A separate 2023 no-spark report involved a points-numbered flywheel, illustrating how difficult it is to interpret failure reports without configuration details. These anecdotes neither establish a failure rate nor prove every complaint is installation error. Owner installation report, no-spark report and flywheel identification.

B. Repair the original Bosch electronics

The long-running Foggysail repair documents bypassing the failed internal capacitor with an externally mounted replacement. The originator discusses roughly 0.8–1.0 µF, at least 400 V, and a capacitor suitable for pulse duty. That is a repair report—not a guarantee that a capacitor is your failed component, and not a generic SEM fix. Original repair discussion, component guidance.

This path makes sense for an electronics-capable restorer who wants to retain the original hardware. Follow the documented circuit identification, not an improvised cut into potting. Winding faults, damaged insulation and other failed components need different remedies. A successful cold spark is only the beginning of validation; insulated connections, secure mounting, hot operation and a functioning stop circuit all matter.

C. Used or new-old-stock Bosch

A correctly matched original set can preserve originality. Ask for the actual markings, lead condition, cold/hot operating evidence and return terms. “Tested” may mean no more than one visible spark. NOS means unused old stock, not recently manufactured electronics.

My purchasing preference would be an identified, returnable replacement over an expensive anonymous “working coil.” That is a risk-management recommendation, not evidence that all old Bosch units are defective.

6. If you have SEM: GE and GA need different decisions

Later GA: retain the correct flywheel if possible

A current original-part seller explicitly limits 1108 400 0800 on the 056 to use with the one-piece 1115 400 1208 flywheel. This is a much more useful fitment statement than a long model list. Forstfritze original-module listing.

If that is already your configuration, investigate a module replacement before financing a whole change of ignition family. Original STIHL-labeled parts and aftermarket 0800 replacements are separate purchasing categories; the number in an advertisement does not make an aftermarket part OEM.

Some sellers describe the service replacement as SEM/Selettra. Treat that as a supplier-description clue, not proof that every Selettra-branded ignition fits. Check the exact part reference and required flywheel. Seller's SEM/Selettra listing.

Early GE: compare complete solutions

The real choice is between a known-good matching GE set, the documented later-SEM conversion, or a Bosch-electronic conversion with its matching 056 flywheel. Do not buy a later GA plate simply because the old component says SEM.

For SEM-to-Bosch, a repairer describes the correct Bosch flywheel, longer stator mounting screws and a female bullet terminal when using the Sägenspezi unit; the existing GE fan was expected to transfer. Treat that as a configuration-specific workshop report, not a universal hardware kit specification. Screw length, thread engagement, lead routing and starter clearance must be checked on the actual combination. 2021 conversion discussion.

Compare the whole installed cost: module, correct rotor, fan/starter pieces, small hardware, shipping and setup labor. A cheap module attached to the wrong flywheel is not a bargain.

7. Concrete-saw and other donor options

The TS360 parts list independently names 1108 400 0800 and its own 1108 400 1205 flywheel. It also lists a 325 mm ignition lead, versus 295 mm in the reviewed 056 IPL. Shared module numbering therefore does not eliminate installation-detail checks. TS360 parts list, electronic ignition, 056 IPL, H.

Sources: STIHL service bulletin, original-module applications, first-hand Dolmar donor reports, 309-to-TS350 report, used SEM GA seller cross-reference.

Do not extend a module cross-reference to a crankshaft taper, rotor or starter. Ask for the donor's actual component markings. An exact component match is stronger evidence than a shared donor model name.

8. Aftermarket options and the current shopping picture

These are advertised prices and page states checked on 17 October 2026, not delivered quotations or verified warehouse inventory. Taxes, international shipping and availability vary. Links are research references, not product endorsements.

FridayParts is another aftermarket lead, with a qualification: its indexed FPCX2504367 product described an 0800 replacement at US$74.99, but opening the product URL returned a missing-page message during this check. Do not treat the search listing's “in stock” label as verified availability. Indexed product URL.

Two first-hand customer reviews of that product report opposite outcomes: one successful SEM replacement and one continuing no-spark problem. They do not identify enough installation details to establish either compatibility across all 056 versions or a meaningful failure rate. Customer reports.

The practical takeaway is that SEM-pattern aftermarket products do exist in listings. Older advice saying there are no aftermarket options is too absolute. Equally, a long compatibility list and a low price are not proof of ignition timing, hot reliability or production consistency.

9. Points conversions and “universal ignition chips”

There are two very different ideas here:

1. A complete, application-specific electronic replacement for a points system. Sägenspezi's points product says the original points flywheel is retained. That is not its Bosch-electronic product and not a stated replacement for SEM. Points-conversion product.
2. Adding a generic trigger module to existing ignition hardware. Nova II sellers explicitly warn against flywheels with multiple magnets. The documented Bosch electronic rotor has a specific multi-pole arrangement. There is no sound basis for treating a generic chip as a universal 056 repair. Nova II restrictions, Bosch service description.

A return to mechanical points has another prerequisite: a suitable crankshaft cam. STIHL T.19.83 records omission of that cam on electronic machines from X 10 963 561. Inspect the actual crankshaft rather than assuming the cam is present—or absent—on a rebuilt saw. Factory engineering change, PDF p. 17.

For most owners, buying a correctly matched replacement system is a more bounded job than engineering a trigger, coil and flywheel combination. Custom conversions deserve their own measured timing and running evidence.

10. Diagnose before ordering; validate after fitting

Before condemning the module

Work through the plug, plug connection, high-tension lead, mounting/grounding and stop-switch wiring. Reproduce the actual complaint: no spark from cold, loss of spark hot, and an engine that stops despite spark are different observations.

One first-hand Bosch repair report recovered spark after isolating faulty stop wiring. That supports checking the circuit—not operating a saw without a stop switch. Restore and verify the stopping function before any running test. Repairer's wiring account.

An ohmmeter can find an open wire or winding, but do not invent a single resistance pass/fail specification for Bosch, GE, GA and aftermarket assemblies. Likewise, an exposed-plug spark is not a complete test of performance under compression and heat. Match the test method to the identified system.

Timing and fit are part of the repair

The early service manual's electronic section gives 2.5–2.7 mm before top dead center; the later SEM bulletin gives 2.8 mm for establishing replacement-crankcase timing marks. Keep those values attached to their respective procedures. Do not average them or present either as a universal aftermarket setting. Early service procedure, printed p. 29, later SEM procedure, PDF p. 38.

For any replacement, require correct seating and retention of the rotor, undamaged keying, adequate lead clearance, suitable fastening and a functioning stop circuit. Set/check timing using the procedure applicable to that assembly. Do not compensate for an unidentified mismatch by filing the key or guessing a stator position.

A satisfactory result should include cold starting, stable operation, hot restart and reliable stopping—not merely “it sparked on the bench.” Any severe starter kickback, contact with rotating parts or loss of the stop function means the installation is not ready for use.

11. What I would buy—and in what order

For a working-saw owner: identify the installed family, eliminate wiring faults, then favor a returnable same-family replacement. Keep a serviceable, correct flywheel. A complete conversion becomes attractive when the original generation is difficult to support, not merely because another coil is cheap.

For a Bosch restoration: compare specialist electronic replacement with repair of the original unit. Keep the original parts even if an aftermarket assembly gets the saw working first.

For an early SEM GE saw: obtain complete prices for both the later factory-style SEM arrangement and a matched Bosch-electronic alternative. The availability and condition of the correct 056 flywheel can decide the economics.

For someone shopping concrete-saw donors: start with identified TS350/TS360 modules; consider the Dolmar 309 as a reported alternative. Request photographs and measurements before paying. Do not purchase a whole machine on the strength of “same ignition.”

Send a seller these five questions

1. What are the exact module and flywheel markings, and can you photograph both sides?
2. Is this Bosch electronic, points, SEM GE, or SEM GA-compatible hardware?
3. Is the price for the coil alone, the populated plate, or a complete matched system?
4. If a flywheel is included, what is its large-end taper-bore diameter and starter arrangement?
5. What was actually tested, and what return coverage applies after fitting if it will not spark or fails hot?

Bottom line: the 056 has viable ignition replacement paths. The best option is determined by the installed ignition family and matching flywheel—not by “Magnum,” “concrete saw,” or “fits 056” in a title.

Sources and scope

Factory evidence: STIHL 056 parts list, July 2004; 045/056 service manual; 056 technical-information compilation, especially T.19.83 and T.13.85; and the TS360 parts-list export. These are manufacturer-authored documents hosted by third parties, not claims that the hosts are STIHL.

Commercial evidence: linked sellers establish their own product descriptions, asking prices and stated availability only. Field evidence: linked owners and repairers describe their own installations or observations; the guide does not promote those reports to manufacturer-approved universal interchangeability.

Remaining gaps: no comparative endurance test, measured spark-energy study, complete supersession history or exact fitment inspection of a reader's saw. Listing prices may change after the review date. This is an independent technical reference, not an official STIHL publication.